CO01671 - Platoro Dam


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Platoro Dam


	Statistics

General

Region (Map) : ................... Upper Colorado

State (Map) ......................... Colorado

County ................................. Conejos

Project: ................................. San Luis Valley

Dam type: ............................ Zoned earthfill

Location: ............................. 1 mi W of Platoro

Watercourse: ...................... Conejos River

Reservoir: ............................ Platoro

Construction Date: .............1949-1951

National ID Number .......... CO01671

Hydrologic Unit Code ......

Dimensions

Crest Elevation of Dam: ..................... 10048.0 ft

Structural Height of Dam .................... 165.0 ft

Crest Length: ...................................... 590.0 ft

Top of Joint Use: ............................... 10027.5 ft

Top of Active Conservation: ........... 10034.0 ft

Top of Inactive Conservation: ....... N/A

Spillway Crest: ................................... 10034.0 ft

Top of Dead Storage: ...................... 9911.4 ft

Streambed at Dam Axis : .................. 9903.0 ft

Hydraulics

Normal Water Surface Elev: ............ 10034.0 ft

Hydraulic Height: ................................. 131.0 ft

Service Spillway Type:

Uncontrolled Crest ..............................Yes

Morning-Glory ......................................... No

Crest Length ........................................ 50 ft

Gated ..................................................... No

Capacity at Elev: 10042.0 ft, 3 ,000 cfs

Auxiliary Spillway ....................................... No

Capacity at Elev. ................................ 0 cfs

Outlet Works Capacity at

Elevation 99630 ft., ..................710.0 cfs

Hydrology

Drainage Area: ................................ 40.0 sq mi

Hydrometeorological Report HMR 55

Flood Type: ............................. Spring General

Storm Duration: ...................................... 72 hrs

Probable Maximum Flood (PMF) Report:

Peak Inflow: .................................... 68,500 cfs

Inflow Volume: ........................ 58,600 acre-ft

Flow Duration: ..................................... 4 days

PMF Routing MWS Elev.: ...................... NA

Initial Routing Elev: ....................... 10027.5 ft

Study Date: .................................. March 1987

Power Generation

Power Generation at Dam Site - None

Bureau of Reclamation Power Program

Narration

Geology

Platoro Dam and Reservoir are located in a geologic area consisting of a complex volcanic bedrock material of, andesite, latite and related rock materials such as breccias and agglomerates. In addition, a unique basaltic material and occasional intrusions are found in the area. Land and rockslides of great magnitude dominate surficial geology. There are two large fault zones that cross the basin at right angles, one about one-half mile upstream and the other about 3 miles upstream. There are, however, three distinct shear zones within the dam and dike foundation area. The damsite bedrock is severely fractured and contains localized shear zones. Some of the shear zones contain highly stained or mineralized vein like material. Exploration indicated the fractures were healed at depth and those that were opened were generally clean and free of mud or other material. The dike and left abutment evidently lie in a huge postglacial rockslide.

Links

| Recreation |

| Dams Located by State | USBR Colorado Dams | Upper Colorado Region Dams |

| Owner: Bureau of Reclamation, Albuquerque Area Office,
505 Marquette NW, Suite 1313, Albuquerque, NM 87102-2162, (505) 248-5357

| Operator: Conejos Water Conservancy District,
Box 550, Manassa, CO 81141, (719) 843-5261